摘要:

AbstractThe fatigue properties of Simplex P and Palacos R bone cements were compared to their antibiotic impregnated counterparts AKZSupported in part by EM Laboratories, 5 Skyline Drive, Hawthorne, NY 10532; and The William H. Harris Foundation.and Palacos R with gentamycinAKZ bone cement is the trade name used by Howmedica Inc. of Rutherford, NJ to describe Simplex P mixed with 0.5 g of erythromycin and 0.24 g of colistin methane sulphonate Both the Simplex P and AKZ cements were obtained from Howmedica. Palacos R and Palacos R with gentamycin (0.5 g/40 g.) were supplied by E. Merck Laboratories.The effect of porosity reduction by centrifugation of all four cement types was also assessed. Fifteen specimens of each cement type were prepared according to manufacturer's instructions and 15 additional specimens of each cement type were prepared by mixing the powder with chilled monomer (0°C) and then centrifuging the cement immediately after mixing. Fifteen fully reversed tension‐compression fatigue tests were performed at 15 MPa in stress control for each cement preparationin vitrowhile simulating thein vivostate (37°C and 100% humidity). The number of cycles to failure were recorded. There was no significant difference in the fatigue life of Palacos R and Simplex P when both cements were prepared in the standard fashion. The addition of 1/2 g of gentamycin to Palacos R did not significantly alter its fatigue properties. The addition of 0.5 g of erythromycin and 0.24 g of colistin did not decrease the fatigue life of Simplex P. Centrifugation significantly improved the fatigue properties of Simplex P and AKZ. The fatigue lives of Palacos R and Palacos R with gentamycin were not improved by centrifugation. The fatigue life of centrifuged Simplex P was significantly greater than the fatigue life of Palacos R and of Palacos R with gentamycin, whether the Palacos R based cements were centrifuged or

ISSN:0021-9304    

DOI:10.1002/jbm.820230402

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractNo difference inin vitroplatelet reactivity was found between an immobilized heparin containing hydrogel (heparin–PVA) and the hydrogel without heparin (PVA), in a variety of experimental assays. There was no significant difference between the heparin–PVA and PVA coated polyethylene tubing in the number of51Cr‐labeled platelets, the extent of14C serotonin release by the adherent platelets or in the degree of platelet count decrease after 1 h exposure to citrated canine whole blood in a Chandler loop system. Furthermore, adhesion and release values were lower than those observed with the uncoated polyethylene tubing (e.g., 9.3 ± 4.3 plt/103μ2on PVA; 18.3 ± 4.6 plt/103μ2on polyethylene). There was also no significant difference between heparin–PVA and PVA in bead column retention values with canine blood and with the previously reported washed human platelet adhesion/release values. Thus there appears to be no effect of the immobilized heparin by itself on thein vitrointeractions of PVA with platelets, with the reactivity towards platelets dominated by that of the underlying substrate

ISSN:0021-9304    

DOI:10.1002/jbm.820230403

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractPolyvinyl alcohol (PVA) hydrogel, with or without heparin, was reactive towards canine platelets in a chronic artriovenous shunt as demonstrated by an increase in platelet regeneration time, a systemic decrease in platelet count and transient decrease in platelet serotonin content. Immobilized heparin (heparin–PVA) had no effect whereas unmodified polyethylene was found to be unreactive despite similar levels of platelet deposition as measured by SEM and a higherin vitroreactivity (J. Biomed. Mater. Res., this is sue). Tewnty‐centimeter lengths of hydrogel coated polyethylene tubing were inserted between the arterial and venous portions of the shunt and left in place for 4–6 days, without the complicating artifacts of anticoagulation, anesthesia, or surgical intervention. Regeneration time was measured as the return to normal platelet cyclooxygenase (co) activity after a single 240‐mg dose of aspirin, with co activity measuredin vitroas malondialde hyde production. Although measuring new platelet production, regeneration time is an indirect measure of platelet consumption, so that the reduced regeneration time seen here was presumed to reflect enhanced material associated consumption and thromboembolism. Like other hydrogels, PVA does not appear to be “thromboadherent” but it does appear thrombogenic. Immobilized heparin had no additional effect, presumably because the platelet response was dominated by the reactivity of the underlyin

ISSN:0021-9304    

DOI:10.1002/jbm.820230404

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractInformation obtained from physical and chemical characterization of vascular grafts can prove valuable in obtaining a preliminary assessment of potentialin vivoperformance. The data presented illustrate the concept and show that the new biological graft made from bovine ureters has adequate performance characteristics for use as a potentially successful vascular graft.

ISSN:0021-9304    

DOI:10.1002/jbm.820230405

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

ISSN:0021-9304    

DOI:10.1002/jbm.820230406

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

ISSN:0021-9304    

DOI:10.1002/jbm.820230401

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY